Take a large stock pot and add the whole roasted chicken. Pour in enough water to just cover the chicken and add the carrots, celery, onion, garlic and thyme. Place over medium heat and slowly bring up to a boil to extract the flavors of the chicken. Simmer for 20-25 minutes then remove chicken and shred meat. Season with salt and pepper and add pasta and shredded meat back into the pot. Gently boil until pasta is cooked and finish with lemon juice and chopped parsley. Taste, and give it a final season with salt and pepper as desired. For preparation of baby food, allow to cool and puree in a food processor.